oil capacity for the rear-gear on a 2021RT?

[explorer]

@explorer

Can u explain to me the differ between the "initial filling" being 200 and the "change oil" being 180

Just guessing (my first 12K mile service coming up next month) but I would assume either:

A) 20ml is undrainable from the assembly once filled; or

B) Initial filling of new final drive allows a higher oil level to ensure running-in lubrication.

But - just a guess from the (not-so) cheap seats!

 

[Wethead]

Makes sense @explorer...thanks

 

[dravnx]

Consider how much difference there is between 200ml and 180 ml, (.67 oz) or about 1/2 a shot glass, it's probably a moot point.

 

[pauls1150]

The initial filling is at the factory, and everything is new and dry inside.
When you change the oil, it's highly likely that you don't get out "all" of the old oil; some will always stick to the gears and housing unless you wash it out with kerosene or gas (and neither is advised unless you actually need to wash out chips from either damage or fill/drain plug hole threads' rework).

 

[milo]

My understanding is it was designed for 220ml in the non vented final drive, but that didn't leave quite enough air for expansion which caused the oil seal to leak. So BMW lowered the recommended fill to 180ml to allow for more air. Since then they've incorporated a vent so from then on they could have gone back to the original 220ml but I never heard either way (but reading this thread they never changed it back it's still 180). Not knowing, for the first FD oil change on my 2014 GSA I carefully measured the original fill that drained out, I let it drain like I always do for around 20-30 minutes, and 200-202ml is what drained out. So I refilled it with 200ml. I did the same on my new (at the time) 2016 RS and just over 200ml drained out, so it gets 200ml too.

 

[20774]

^^^ Nice, milo! That basically takes care of any issues and discrepancies in some book!!

 

[milo]

Well in my sample of two.

 

[mathoma]

My 2021 RT does not call for the final drive oil to be changed during the 1st run in service like my 2 previous wetheads did (2015 & 2018). When I purchased the bike I went ahead a bought the new final drive fluid and oil rings and plan on changing it myself at 700 miles.

 

[Omega Man]

I vote for 190ml.
OM

 

[riderr1150gsadv]

^ that is a nice middle ground there... I add Moly paste to my FD oil and so far it worked on my oil-head and wet-head bikes... YMMV

 

[jandhumphreyme]

@explorer

Can u explain to me the differ between the "initial filling" being 200 and the "change oil" being 180

about 1.35 tablespoons

 

[motodan]

about 1.35 tablespoons

Your reply is almost three years late. No doubt OP’s final drive has already exploded!

 

[Toruk]

BMW sells a 200ml bottle for service. OIl drain and fill is 180ml. Disassemble, clean and fill from a DRY gear condition is 200ml.

 

[pauls1150]

The initial filling is for a dry unit, freshly assembled at the factory.
20 mL = 20 cc = 0.676 oz (U.S.) =1.35 tablespoon
They're accounting for the leftover oil sticking to the gears and housing when the oil is changed.

 

[BC1100S]

Your reply is almost three years late. No doubt OP’s final drive has already exploded!

One can hope.

 

[lee]

20 mL = 20 cc = 0.676 oz (U.S.) =1.35 tablespoon

Canadian or US tablespoon

 

[pauls1150]

U.S. of course! The Canookian is more like a ladle...

 

[BC1100S]

You guys......

 

[pauls1150]

Down hea, one tablespoon is also 3 teaspoons.
BUT - There is also a difference (naturally...) between a U.S. and a British tablespoon:
In the British system, one tablespoon is equivalent to 17.7582 milliliters; in the American system, it’s 14.7868 milliliters. (Source: errenskitchen.com) It's probably more important for recipes than for oil.

 

[taran1900]

Consider how much difference there is between 200ml and 180 ml, (.67 oz) or about 1/2 a shot glass, it's probably a moot point.

It's not a moot point. If you overfill there is the possibility of blowing out a seal. Don't ask me how I know this.